This invention relates to surgical swabs, and to a process for producing such swabs.
Swabs used in surgical procedures are usually of three types, namely those used for skin preparation, those used for absorbing body fluids during a surgical operation, and those used for packing the body cavity while surgical work is carried out on the viscera. For each of these purposes, a surgical swab should have wettability, flexibility, softness of handle and a degree of resilience, particularly when wet. Swabs which are to be used within the body cavity should also be provided with means for locating the swab, since such swabs can otherwise be difficult to identify when saturated with blood or other body fluids.
Surgical swabs are conventionally manufactured by sewing together sufficient layers of a woven light surgical gauze or muslin to achieve the required thickness. The use of a large number of plies of a lighter woven fabric is preferred to the use of fewer plies of heavier woven cloths. Heavy woven cloths normally lack flexibility, and have relatively low absorbency because of the lack of interlayer capillaries.
Conventional surgical swabs are usually provided with a handling tape for locating the swab, such handling tapes usually being formed from a length of woven cotton fabric.
British Patent Specification No. 1478454 discloses a surgical swab which is cut from a length of warp or weft knitted fabric. The or each cut edge of the swab is enclosed within a folded tape, the tape being folded over the cut edge with the side edges of the tape tucked in and the tape secured to the cut edge of the swab. The purpose of this arrangement is to obviate possible fiber loss from the cut ends of the swab and from the side edges of the tape. Fiber loss is, of course, highly undesirable because discarded fibers may be retained in the body cavity of a patient, with consequent adverse effects.
The above-mentioned Specification also discloses that one of the edge tapes applied to the swab may extend beyond the width of the swab to act as a handling tape for locating the swab during surgical operations.
The swabs disclosed in Specification No. 1478454 have certain advantages over the conventional muslin swabs. A knitted structure differs from a woven fabric in that it consists of threads interlaced by looping. This looped structure tends to make knitted fabrics more flexible, more deformable and thus apparently much softer to handle than a woven material of equivalent weight. Both warp and weft knitted structures can be produced which have the resilience, wettability and absorbency of a multiplicity of layers of conventional woven fabrics.
Despite these advantages the surgical swabs of Specification No. 1478454 has not received the anticipated commercial acceptance, most probably because of the relatively high cost of the manual operations involved in converting the knitted fabric into swabs.